Module 1 - cells
Prokaryotic cells
A microscopic single-celled organism which lacks a nucleus and other membrane
bound organelles
● Plasmid: extra circular loops of DNA
● Ribosome: not bound by membrane and made of ribosomal RNA and protein
● Floating membrane
Pili
●Hair-like structure on cell surface
●Injects plasmid into other bacteria
○ Plasmid can divide and reproduce inside cell independent of
chromosome
○ Plasmids can be shared between bacteria
Flagella
● Propels bacteria through a fluid
● Some eukaryotic cells (sperm) have flagella
Eukaryotic cells
An organism consisting of a cell or cells in which there is a distinct membrane-bound
nucleus and organelles
Organelles
Nucleus
● Large spherical
● Double membrane
, ● Contains most DNA
● Controls cell activity by determining which proteins will be synthesized at
ribosome
● Contains nucleolus
○ Where ribosomal RNA is synthesized
Ribosomes
● Site of protein synthesis
● Made of ribosomal RNA and protein
● Free in the cell
Endoplasmic Reticulum (ER)
● Networks of flattened membrane bound sacs
● Runs through cytoplasm (‘road network’)
● Transports materials
● RER: transports proteins on attached ribosomes
● SER: transports of other compounds (e.g. lipids)
Mitochondria
● Powerhouse of the cell
● Double membrane
● Cristae: inner ripples
● Matrix: fluid
● Where ATP is produced during cellular respiration
Golgi body
● Stack of flattened sacs
● Receives proteins from ER
● Proteins synthesized on ribosomes in RER moves into Golgi apparatus
● Site where proteins get packaged and modified into vesicles (e.g. add sugar)
● Vesicles export protein from the cell (exocytosis)
Centriole
● Small protein tubes of microtubules
● Organises spindles during cell division
● No centriole in plant cell
Cilia and flagella
● Protuberances from cell membranes
● Similar structure
○ Cilie is shorter
● In multicellular organisms:
○ Pushes fluid against it
○ Cell stays where it is
● Has protein microtubules running in pairs down its length
● Bacterium (prokaryote) flagellum is made of a single protein
Chloroplast
● Double membrane separated by fluid-filled space
● Thylakoid: smaller membrane bound pouches
○ Appear in stacks (granum)
● Stroma: fluid filled space between granum
● Have their own DNA
● Chlorophyll molecules present
● Site of photosynthesis
Prokaryotic cells
A microscopic single-celled organism which lacks a nucleus and other membrane
bound organelles
● Plasmid: extra circular loops of DNA
● Ribosome: not bound by membrane and made of ribosomal RNA and protein
● Floating membrane
Pili
●Hair-like structure on cell surface
●Injects plasmid into other bacteria
○ Plasmid can divide and reproduce inside cell independent of
chromosome
○ Plasmids can be shared between bacteria
Flagella
● Propels bacteria through a fluid
● Some eukaryotic cells (sperm) have flagella
Eukaryotic cells
An organism consisting of a cell or cells in which there is a distinct membrane-bound
nucleus and organelles
Organelles
Nucleus
● Large spherical
● Double membrane
, ● Contains most DNA
● Controls cell activity by determining which proteins will be synthesized at
ribosome
● Contains nucleolus
○ Where ribosomal RNA is synthesized
Ribosomes
● Site of protein synthesis
● Made of ribosomal RNA and protein
● Free in the cell
Endoplasmic Reticulum (ER)
● Networks of flattened membrane bound sacs
● Runs through cytoplasm (‘road network’)
● Transports materials
● RER: transports proteins on attached ribosomes
● SER: transports of other compounds (e.g. lipids)
Mitochondria
● Powerhouse of the cell
● Double membrane
● Cristae: inner ripples
● Matrix: fluid
● Where ATP is produced during cellular respiration
Golgi body
● Stack of flattened sacs
● Receives proteins from ER
● Proteins synthesized on ribosomes in RER moves into Golgi apparatus
● Site where proteins get packaged and modified into vesicles (e.g. add sugar)
● Vesicles export protein from the cell (exocytosis)
Centriole
● Small protein tubes of microtubules
● Organises spindles during cell division
● No centriole in plant cell
Cilia and flagella
● Protuberances from cell membranes
● Similar structure
○ Cilie is shorter
● In multicellular organisms:
○ Pushes fluid against it
○ Cell stays where it is
● Has protein microtubules running in pairs down its length
● Bacterium (prokaryote) flagellum is made of a single protein
Chloroplast
● Double membrane separated by fluid-filled space
● Thylakoid: smaller membrane bound pouches
○ Appear in stacks (granum)
● Stroma: fluid filled space between granum
● Have their own DNA
● Chlorophyll molecules present
● Site of photosynthesis
